Lead-in terminal unit for rotary directional antennae



June 19, 1951 H. BROOKS 2,557,074

LEAD-IN TERMINAL UNIT FOR ROTARY DIRECTIONAL ANTENNAE Filed April 22,1947 2 Sheet's-Sheet 1 June 19, 1951 v BROQKS 2,557,074

LEAD-IN TERMINAL UNIT FOR ROTARY DIRECTIONAL ANTENNAE Filed April 22,1947 2 Sheets-Sheet 2 IN V EN TOR.

Patented June 19, 195T LEAD-IN TERMINAL UNIT FOR ROTARY DIRECTIONALANTENNAE Herbert Brooks, Middleboro, Mass.

Application April 22, 1947, Serial No. 743,147

This application relates to a feeder or lead-in terminal unit for rotarydirectional antennae.

At the present time directional antennae are mounted on rotary mastsarranged for rotary movements through an angle of 180. These masts areusually made up from sections of conventional pipe. The feeders orlead-in wires are draped along the outside of the mast. As the mastsrotate, first in one direction and then in the opposite direction, thelead-in wires become worn in spots developing radio frequency leaks andfinally short circuits.

It is a primary object of the present invention to bring the lead-inwires down the interior of the mast, that is, approximately along thecenter line of rotation of the mast, where they will not be subject tobeing wound and unwound a the mast rotates.

It is another object of the present invention to provide a terminal unitfor attachment to the mast, whereby the lead-in conductors within themast are maintained in continuous electrical connection with extensionconductors leading to the receiver, or transmitter, as the case may be.

It is a further object of the present invention to provide a terminalunit for attachment to the mast and for connection of the lead-inconductors therein to extension conductors, which unit may be readilyattached to the mast with a minimum modification of the latter.

Still other objects, advantages and improvements will become apparentfrom the following description, taken in connection with theaccompanying drawings, in which:

Figure l is a side elevational view showing a portion of a mast with acasing enclosing the terminal unit of the present invention mountedthereon;

Figure 2 is a sectional view on the section line 2-2 of Figure 1,showing the upper spring assembly in contact with one of the collectorrings;

Figure 3 is an end elevational view of the casing which encloses theterminal unit, this view showing the terminals for the receiver andtransmitter connections, as the case may be;

Figure 4 is a top plan view showing one modification of the wiper springassembly in contact with a collector ring;

Figure 5 is an enlarged and partially exploded view of the terminalunit;

Figure 6 is a vertical sectional view through the mast and the terminalunit.

Referring now to the drawings in detail, and to Figure 6, in particular,this figure shows the mast at with lead-in conductors H and I2 extendingdown the interior of the same. It willbe 2 Claims. (01. 173-324)understood that these conductors extend from an antenna carried by themast and enter the mast through a suitable grommet in the side wall nearthe top of the same. This latter feature formsno part of the presentinvention and is not here illustrated. The lead-in connectors H and I 2material, such as Bakelite, is mounted over the flanges IT--l'i on thesleeves Iii-l6 and i secured to these flanges by annular rows ofradially positioned set screws I9. The insulating sleeve 20 has twocircumferential grooves 25 and 26 thereon, these grooves beingrectangular in crosssection. Within the grooves 25 and 26 there aremounted fiat collector rings 29 and 30, respectively, these being madeof brass, copper, or other suitable metals or alloys. The collectorrings 29 and 30 may be of split construction and may be sprung intoplace in the grooves 25 and 26, respectively. Diametrically opposedholes 2| and 22 are formed through the cylindrical sleeve 20,intermediate the grooves 25 and 26, and from the hole 2| a longitudinalchannel 23 extends to the groove 25; similarly, from the hole 22 alongitudinal channel 24 extends in the opposite direction to the groove26. The lead-in conductor ll extends through the hole 2| and channel 23to the ring 29 in the groove 25, being connected to the ring through alug 21 positioned in the channel 23; likewise, the lead-in conductor i 2extends through the hole 22 and channel 2t to the ring 30 in the groove26, being connected to the ring antenna are transmitted by the lead-inconductors II and 12 through the collector rings 29 and 30, respectivelyFrom these rings they are picked up by wiper spring assemblies. Figure 2shows only the upper wiper spring assembly. in contact with the uppercollector ring 29. This device, as here shown, is comprised of anarcuate spring member 3| having an integral central boss 33, the radiusof curvature of the spring section 3| being less than that of thecollector ring 29. A screw-threaded rod 35 is mounted in the boss 33 onthe arcuate spring member 3|, this rod having a first pair of opposednuts 31-31 thereon on either side of an end panel 5?. of a casing, and asecond pair of opposed nuts 3 939 thereon between which latter theextension conductor 4| is secured; the extension conductor 4| extends tothe radio receiver, or transmitter, as the case may be. It will beunderstood that the second or lower wiper spring assembly is identicalin construction with the first, only the threaded rod 36 and theexternal nut 38 of the first pair, the second pair of nuts ii)@-fl, andthe conductor 52 gripped therebetween being shown in Figure 1.

Figure 4 shows a modification of the wiper spring assembly. In thismodification, the screwthreaded rod 35 or 35, as the case may be, has aclosed end ferrule 53 on its inner end. The Wiper spring 45 proper isformed of truncated V construction, secured at its flattened apex to theferrule 53 by screws ll. The outer ends of the wiper spring are bentoutwardly, as at 49. Again, it will be understood that the second wiperspring assembly is identical to that here disclosed. The entire rotaryterminal unit is enclosed b a weatherproof box comprised principally ofa main body 51] of U-shaped construction. Over the open end of theU-shaped body an end panel 52 is secured by suitable screws 5i extendinginto suitable end flanges (not shown) on the U -shaped body. The endpanel 52 is made of some suitable insulating material, such as Bakelite.The casing has a bottom (not shown) and a removable top 54 which issecured to the U-shaped body 50 by screws 53 extending into inturnedflanges (not shown) on the body. The top 5 and the bottom (not shown)are provided with aligned holes adapted to receive the hubs of thesleeves l6--IB.

As previously stated, the screw-rods 35 and 3e: extend through suitableholes in the insulated end panel 52, and these rods may be shiftedthrough the end panel by adjusting the pairs of nuts 3l3l and 38t8,respectively, to var the contact pressure of the wiper spring assemblieson the collector rings 293t, respectively.

The operation of the lead-in terminal unit should be obvious from thepreceding description. It may, however, be summarized as follows:

The directional antenna is carried by the mast ll) which is adapted torotate through an angle of 189. Since the lead-in conductors I1 and I2are adjacent the axis of the mast, these are subjected to a minimum oftorsional stress. The radio frequency pulsations induced in the antennaare carried through the lead-in conductor II, collector ring 29, wiperspring 3!, rod 35, and conductor 4!, to the receiver or transmitter, asthe case may be; similarly, the lead-in conductor I2 is connectedthrough the collector ring 30, and through the lower wiper spring (notshown), the rod 36, and the conductor 52 again to the receiver ortransmitter, as the case may be.

It will be apparent that, while the preceding description and annexeddrawings present the invention in its preferred embodiment, variouschanges may be made in the size, proportions, and relative arrangementof the various parts without departing from the spirit of the inventionas defined in the appended claims Having now described my invention,what I claim as new and useful and desired to secure by.

Letters Patent of the United States is:

1. In a terminal unit for a hollow rotatable antenna with a hollow masthaving a pair of diametrically-opposite and downwardly-directedapertures, a casing enclosing the terminal unit with the latterrotatably mounted in the casing, an insulated wall upon the latter, apair of wiper spring contacts supported inwardly of the insulated wallwithin said casing and having terminal portions extending externallyupon said insulated wall for a connection with a pair of externalconductors, and a pair of internal conductors in the H hollow mastextending with the ends thereof outdisposed and diametrically oppositeapertures and a pair of longitudinally-directed channel portionsexteriorly connecting one of the latterapertures in one direction withone of the annular recesses and the other of the apertures in theopposite direction with the other of the annular recesses, a pair ofcollector rings seated in said annular recesses and engaged by saidwiper spring contacts, and a pair of lugs individually disposed on thecollector rings and seated in said longitudinally-directed channelportions upon said insulating sleeve, and the outwardlyextending ends ofsaid internal conductors projecting through said centrally-disposedapertures and being individually connected to the lugs on said collectorrings.

2. In a terminal unit for a hollow rotatable antenna with a hollow masthaving a pair of diametrically-opposite and downwardly-directedapertures, a casing enclosing the terminal unit with the latterrotatably mounted in the casing,

an insulated wall upon the latter, a pair of wiper spring contactssupported inwardly of the insulated wall within said casing and havingterminal portions extending externally upon said insulated wall for aconnection with a pair of external conductors, and a pair of internalconductors in the hollow mast extending with the ends thereof outwardlythrough the opposite and downwardly-directed apertures in said hollowmast, the features which include a pair of opposed sleeves secured uponthe latter mast in spaced-apart relation, an insulating sleeve ofsubstantially the same internal diameter as the external diameters ofthe mutually-opposite ends of the pair of opposed sleeves and fittingupon the latter in such manner as to bridge the resulting space betweensaid opposed sleeves, the

insulating sleeve being provided with a pair ofannular recesses spacedapart and located be-;

other of the apertures in the opposite directionwith the other of theannular recesses, a pair of collector rings seated in said annularrecesses and engaged by said wiper spring contacts, and

5 6 a pair of lug individually disposed on the rings REFERENCES CITEDand seated in said longitudinally-directed chan- The followingreferences are of record in the nel portions upon said insulatingsleeve, and the me of this patent: outwardly-extending ends of saidinternal conductors projecting outwardly through the space 5 UNITED.STATES PATENTS between said pair of opposed sleeves and bridged NumberName Date by said insulating sleeve and then out through 529,898 CurryNov 27, 1894 said centrally-disposed apertures in the latter 1,142,257Huff June 8, 1915 and being individually connected to the lugs on1,430,656 Blackb r Jan, 15, 1924 said collector rings externally uponsaid insulat- 10 2,309,316 Hollander Jan, 26, 1943 mg sleeve.

HERBERT BROOKS.

